This proposal requests research and infrastructural support for the Population Studies & Training Center (PSTC) at Brown University. The primary mission of the PSTC is to produce and disseminate innovative research on the causes and consequences of population size, composition, distribution and well-being in the U.S. and around the world. It carries out this mission by providing state-of-the-art facilities and research support to PSTC associates; maintaining a forum for intra- and inter-disciplinary exchange on population related issues; supporting a high-quality graduate training program; facilitating the recruitment and development of population-related faculty at Brown; and developing cross-unit collaborations on campus and with institutional partners around the world. The PSTC is distinguished by its deep level of engagement with three social-science departments -- Anthropology, Economics, and Sociology -- as well as thematically driven links to scholars in other campus departments and a long-standing university-wide commitment to interdisciplinary activity. It has developed particular expertise in primary data collection in low-income countries; the integration of a broad spectrum of different methodological perspectives; and innovative methods of using spatial data to address important social issues. Research focuses on social structures and systems that influence population change and targets four substantive themes. The first theme considers how social, economic, cultural and political institutions influence the process of demographic change in the Global South. The second examines social, behavioral and physiological sources of persistent disparities in health and human capital. The third explores the role of migration in transferring not just people, but resources, institutions and ideas. The fourth focuses on two substantive areas in which spatial structures play a key role in determining population health and well-being: urbanization and population-environment interrelations. A combination of broad methodological expertise and thematic coherence creates a fertile medium that nurtures innovative scholarship, promotes the development of junior scholars, and influences the trajectory of population research.